A dissipative reaction network drives transient solid-liquid and liquid-liquid phase cycling of nanoparticles

Financial support for this work was provided by the University of St Andrews and EaStCHEM, and the Leverhulme Trust [Grant RPG-2019-155].Transient states maintained by energy dissipation are an essential feature of dynamic systems where structures and functions are regulated by fluxes of energy and matter through chemical reaction networks. Perfected in biology, chemically fueled dissipative networks incorporating nanoscale components allow the unique properties of nanomaterials to be bestowed with spatiotemporal adaptability and chemical responsiveness. We report the transient dispersion of gold nanoparticles in water, powered by dissipation of a chemical fuel. A dispersed state that is generated under nonequilibrium conditions permits fully reversible solid–liquid or liquid–liquid phase transfer. The molecular basis of the out-of-equilibrium process is reversible covalent modification of nanoparticle-bound ligands by a simple inorganic activator. Activator consumption by a coupled dissipative reaction network leads to autonomous cycling between phases. The out-of-equilibrium lifetime is tunable by adjusting pH, and reversible phase cycling is reproducible over several cycles.Publisher PDFPeer reviewe

Solving Multi-Objective Voltage Stability Constrained Power Transfer Capability Problem using Evolutionary Computation

Competitive market forces and the ever-growing load demand are two of the key issues that cause power systems to operate closer to their system stability boundaries. Open access has since introduced competition and therefore promotes inter-regional electrical power trades. However, the economic flows of electrical energy between interconnected regions are usually constrained by system physical limits, e.g. transmission lines capacity and generation active/reactive power capability etc. As such, there is a limitation to the capacity of electrical power that regions can export or import. This maximum allowable electrical power transfer is normally referred to as Total Transfer Capability (TTC). It is critical to understand that TTC does not necessarily represent a safe and reliable amount of inter-regional power transfer as one or more operational limits are usually binding when quantifying TTC. Hence, it is of interest that power system stability issues are being considered during power transfer capability assessment in order to provide a more appropriate and secure power transfer level.The aim of this paper is to formulate an Optimal Power Flow (OPF) algorithm, which is capable of evaluating inter-area power transfer capability considering mathematically-complex voltage collapse margins. Through a multi-objective optimization setup, the proposed OPF-based approach can reveal the nonlinear relationships, i.e. the pareto-optimal front, between transfer capability and voltage stability margins. The feasibility of this approach has been intensively tested on a 3-machine 9-bus and the IEEE 118-bus systems

The efficacy of interpersonal psychotherapy for depression among economically disadvantaged mothers

A randomized clinical trial was conducted to evaluate the efficacy of interpersonal psychotherapy (IPT) for ethnically and racially diverse, economically disadvantaged women with major depressive disorder. Non-treatment-seeking urban women (N = 128; M age = 25.40, SD = 4.98) with infants were recruited from the community. Participants were at or below the poverty level: 59.4% were Black and 21.1% were Hispanic. Women were screened for depressive symptoms using the Center for Epidemiologic Studies Depression Scale; the Diagnostic Interview Schedule was used to confirm major depressive disorder diagnosis. Participants were randomized to individual IPT or enhanced community standard. Depressive symptoms were assessed before, after, and 8 months posttreatment with the Beck Depression Inventory—II and the Revised Hamilton Rating Scale for Depression. The Social Support Behaviors Scale, the Social Adjustment Scale—Self-Report, and the Perceived Stress Scale were administered to examine mediators of outcome at follow-up. Treatment effects were evaluated with a growth mixture model for randomized trials using complier-average causal effect estimation. Depressive symptoms trajectories from baseline through postintervention to follow-up showed significant decreases among the IPT group compared to the enhanced community standard group. Changes on the Perceived Stress Scale and the Social Support Behaviors Scale mediated sustained treatment outcome

A systematic review of interventions on body image and disordered eating outcomes among women in midlife

Objective: Body dissatisfaction and disordered eating are widely recognised as issues that warrant attention among women in midlife, particularly the development and delivery of effective interventions. This paper systematically reviews existing research on interventions among midlife women on body image and disordered eating outcomes, in order to inform intervention delivery and provide strategic directions for future research.Method: Fourteen electronic databases were searched for articles published between 1992-2015 that evaluated interventions with non-clinical samples of women (M age 35-55 years) in controlled trials with at least one body image measure. Data were extracted and evaluated, and the methodological quality of studies was assessed using the Cochrane Collaboration tool for assessing risk of bias.Results: From 7,475 records identified, 9 articles evaluating 11 interventions met the inclusion criteria. Seven interventions significantly improved body image at post-test (ds = 0.19-2.22), with significant improvements on disordered eating achieved by two of these interventions (ds = 0.90-1.72). Sustained improvements were achieved by three interventions that employed a multi-session, therapeutically based, group intervention format; two with sustained body image and disordered eating improvements, and one with sustained body image improvements only (ds = 0.55-1.21; 2 weeks-6 months). Methodological quality varied between studies. Discussion: To date, three interventions have demonstrated sustained improvements and are indicated for practitioners aiming to improve body image and disordered eating among women in midlife. Replication and more rigorous randomised controlled trials are required to enhance the methodological quality of intervention studies in this field

Application of multi-objective evolutionary optimization algorithms to reactive power planning problem

This paper presents a new approach to treat reactive power (VAr) planning problem using multi-objective evolutionary algorithms (EAs). Specifically, strength Pareto EA (SPEA) and multi-objective particle swarm optimization (MOPSO) approaches have been developed and successfully applied. The overall problem is formulated as a nonlinear constrained multi-objective optimization problem. Minimizing the total incurred cost of the VAr planning problem and maximizing the amount of available transfer capability (ATC) are defined as the main objective functions. The aim is to find the optimal allocation of VAr devices in such a way that investment and operating costs are minimized and at the same time the amount of ATC is maximized. The proposed approaches have been successfully tested on IEEE 14 buses system. As a result a wide set of optimal solutions known as Pareto set is obtained and encouraging results show the superiority of the proposed approaches and confirm their potential to solve such a large-scale multi-objective optimization problem